1. Field of the Invention
The present invention relates to an operation control device and an operation control method for a cooling apparatus that has a compressor driven by a speed-controlled electric motor and cools the inside of a storehouse such as a refrigerator, freezer or the like.
2. Description of the Prior Arts
It has conventionally been well-known that an inside temperature of a storehouse is detected and a speed of an electric motor is controlled by using this detected inside temperature as disclosed in, for example, Japanese Unexamined Patent Application No. HEI11-173729 and Japanese Unexamined Patent Application No. SHO60-188775. In this case, the rotational speed of the electric motor is controlled to be increased as the detected inside temperature rises from a preset temperature to thereby enhance a cooling ability of the cooling apparatus, whereby the inside temperature is returned to the preset temperature in a short period and the inside temperature is kept to be approximately equal to the preset temperature even if the inside temperature rises from the preset temperature.
However, in the above-mentioned conventional device, in case where an extremely high inside temperature that is close to the ambient temperature is lowered to the preset temperature like the case of starting the operation of the cooling apparatus, the rotational speed of the electric motor is controlled to be extremely fast since the inside temperature is quite higher than the preset temperature at the beginning. Great current flows through the electric motor when the rotational speed of the electric motor is extremely fast. Allowing this great current to flow requires an electric motor and power circuit having a large capacity, thereby entailing a problem of leading to a large-sized electric motor and power circuit, that consequently leads to increased production cost.